胎鼠中脑多巴胺细胞混合培养方法探索

目的 探索一种新的胚胎大鼠腹侧中脑黑质细胞的混合培养方法,以获得具有高比例多巴胺神经元的原代细胞体系,有利于在体外条件下进行帕金森病(Parkinson's disease,PD)的发病机制和防治的研究.方法 分离E15 (Embryonic Day 15)SD胎鼠中脑黑质区域组织,分散为单细胞后,分别用DMEM/F12+ 10％FBS含血清培养基和Neurobasal+ N1无血清培养基设置不同组别进行培养,通过免疫组织化学方法检测在不同培养条件下细胞的生长状态及多巴胺能神经元的比例.结果 DMEM/F12+ 10％ FBS与Neurobasal+ N1先后一周交替换液的的培养体系中获得的TH阳性神经元占神经元的比例可达31％左右,明显高于单独使用DMEM/F12+ 10％ FBS培养组(约10％).结论 DMEM/F12+ 10％ FBS与Neurobasal +N1先后一周交替换液是一种黑质神经元和胶质细胞混合培养并能获得高比例多巴胺神经元的有效培养方法.     

人正常食管鳞状上皮不同原代培养方法的比较

该研究通过比较人正常食管鳞状上皮不同的原代培养方法,以期为不同的实验目的提供不同的培养方法。实验用到的正常食管粘膜上皮来源于食管癌患者手术切除的标本,采用组织块法和酶消化法,分别用DMEM/F12混合培养基和K-SFM无血清培养基进行培养。通过直接观察、细胞形态学观察和免疫细胞化学方法观察细胞的生长情况、细胞形态学特征及鉴定所得到的细胞,比较不同方法与不同培养基组合中原代培养细胞的生长状况。用组织块法,在DMEM/F12混合培养基中人正常食管上皮细胞生长较好,细胞融合较快,成纤维细胞污染较少,15～17天上皮细胞铺满瓶底的70%～80%,获得的细胞数量大,但细胞传代后成纤维细胞污染严重。用酶消化法,在K-SFM无血清培养基中人正常食管上皮细胞生长好,细胞融合快,成纤维细胞污染基本消除,细胞纯度高,10～12天细胞便可以铺满瓶底的70%～80%,这种方法培养的细胞可以冻存、复苏和传代。其余各种培养方法所得细胞无论在生长状态、培养周期、成纤维细胞污染和传代方面均较前两种方法差。以上各种方法培养的细胞经免疫细胞化学染色鉴定证实细胞呈广谱细胞角蛋白阳性,确定是食管上皮来源的细胞。酶消化法加K-SFM无血清培养基是本实...     

CHO细胞法检测百日咳毒素毒性的影响因素

目的考察不同培养基、不同牛血清、血清灭活与否及生产过程中添加的各外源物质对百日咳毒素(pertussis toxin, PT)在中华仓鼠卵巢细胞(chinese hamster ovary cell, CHO)簇集试验中的影响。方法分别使用3种培养基F-12K、DMEM/F12和1640培养CHO细胞,并进行CHO细胞簇集试验,观察细胞生长状态及PT引起细胞簇集的敏感性;分别选取2个厂家的牛血清(对2种血清进行灭活和不灭活处理)培养CHO细胞,观察4种牛血清对细胞生长及簇集的影响;选用生产过程中添加的物质进行CHO细胞簇集试验,观察细胞生长状态及是否出现簇集,确定不影响细胞生长的最高浓度,同时使用不影响细胞生长的各添加物质最高浓度进行小鼠组胺致敏试验,观察与CHO细胞簇集试验结果是否一致。结果 3种培养基对CHO细胞生长及CHO细胞簇集存在明显差异,F-12K培养基培养的细胞形态规则、典型,其他2种培养基培养的细胞生长缓慢,且对PT的敏感性均低于F-12K培养基;4种牛血清中胎牛血清培养的细胞生长最快且形态规则,簇集试验敏感性优于其他3组血清;添加的各外源物质均会导致细胞生长缓慢或死亡,在稀释至一定浓度后可以排除添加物质对CHO细胞簇集试验的影响,同时在小鼠组胺致敏试验中不会引起动物死亡。结论 F-12K培养基最适宜实验室CHO细胞生长,不同血清对细胞生长和簇集的敏感度有一定差异,添加的外源物质残留量应进行控制以保证试验结果的稳定可靠。     

不同培养基中MDCK细胞生长及代谢动力学研究

[目的]为筛选适应于MDCK细胞大规模培养的最佳培养基并揭示其代谢动力学规律。[方法]选取商业化的培养基DMEM(试验组A)、EMEM(试验组B)、MEM(试验组C)、M199(试验组D)、DMEM/F12(试验组E)及DMEM:EMEM复合培养基(试验组F)用于MDCK细胞传代培养,研究不同培养基对MDCK细胞生长特性的影响,分析MDCK细胞生长过程中葡萄糖(Gluc)、乳酸(Lac)、谷氨酰胺(Gln)和氨(NH4+)的代谢情况,并进一步进行细胞工厂的培养验证。[结果]结果表明MDCK细胞均能在试验组A、B、E、F四种培养基中生长,其最大增殖浓度E A F B,差异显著(P 0. 05);倍增时间B F A E,差异显著(P 0. 05);细胞比生长速率E A F B,差异不显著(P 0. 05)。不同培养基培养MDCK细胞对数生长期平均葡萄糖比消耗速率、谷氨酰胺比消耗速率及氨比生成速率差异均不显著(P 0. 05),乳酸比生成速率差异显著(P 0. 05)。在试验组A和E培养基中细胞能实现高密度增殖,再将其进行细胞工厂扩大培养验证,发现两种培养基在培养48 h时均能达到单层致密,且细胞密度均达到8. 0×10~8/cells以上,差异不显著(P 0. 05)。[结论]综合研究结果及规模化生产成本因素,采用DMEM培养基(试验组A)培养MDCK细胞,其最大增殖浓度达到6. 4×10~5/m L,倍增时间为22. 835 h,比生长速率为0. 558,可进行大规模培养,为工业化生产提供依据。     

OLN-93细胞系分化条件探讨

目的 OLN-93细胞是实验室常用的少突胶质前体细胞细胞系,多被用于研究少突胶质细胞的分化。本文来探讨OLN-93细胞系的最佳分化条件。方法分别用DMEM、DMEM+三碘甲状腺原氨酸(T3)、DMEM+T3+N2、DMEM/F12、DMEM/F12+T3、DMEM/F12+T3+N2等6种不同培养基条件对OLN-93细胞系进行分化处理,于处理后的第3d和第6d观察细胞形态变化并通过免疫荧光技术鉴定细胞分化情况,同时通过检测髓鞘主要标志物MBP、CNP基因的mRNA和蛋白质的表达情况来分析细胞的分化状态,从而筛选出OLN-93细胞的最优分化培养基。结果比较OLN-93细胞在6种不同条件下的分化情况,免疫荧光、qPCR和Western Blot检测显示出基本一致的结果,DMEM培养基中的细胞分化状态最好,其次为DMEM+T3组,而DMEM+T3+N2和DMEM/F12+T3+N2组最差。结论 DMEM培养基为适宜OLN-93细胞生长分化的最佳培养条件,其他成分如F12、N2均会不同程度的抑制细胞的分化。我们实验发现OLN-93已经丧失了对T3的反应,这一点在使用OLN-93细胞的实验研究中需要加以考虑。     

利用高通量生物反应器优化一种CHO细胞无血清培养基

研究以DMEM/F12(1:1 V/V)培养基为基础,添加不同添加剂优化一种适宜CHO DG44细胞生长的廉价培养基。以细胞密度和细胞活率为主要指标,对DMEM/F12(1:1 V/V)培养基进行了优化。通过正交试验和单因素试验筛选出了CHO DG44细胞生长的最佳培养基。正交试验结果表明添加8mg/L Insulin、10mg/L Transferrin、12mM Glutamine、9mg/L Ethanolamine、9mg/L Sodium selenite、0.5×Lipids、0.5×Vitamin,对细胞生长有较好促进作用,细胞密度从0.6×106 cells/mL上升到1.8×106 cells/mL。在此基础上添加2.5g/L Malt Peptone和2.5g/L YeastExtract可使细胞密度达到2.65×106 cells/mL,基本上达到商业培养基的培养效果,而成本降低了约60%。     

培养基血清浓度对人表皮干细胞增殖分化的影响

目的:比较不同血清浓度培养体系对表皮干细胞增殖分化的影响.方法:采用两步酶消化法和IV型胶原差速贴壁相结合的方法获得人原代表皮干细胞,分别以0%、5%、10%、15%和20%血清浓度的培养基在96孔板中进行培养.观察表皮干细胞形态,克隆形成及增殖的情况,应用四甲基偶氯唑蓝(MTT)比色法检测各组细胞存活和生长情况,分析量效和时效关系;持续传代培养细胞,每次传代的同时取适量细胞,用免疫细胞化学的方法进行表皮干细胞和表皮细胞相应标志物(K19、K14和K10)的测定.结果:表皮干细胞在各种血清浓度的培养基内均能形成克隆,增殖良好.用四甲基偶氮唑蓝(MTT)比色法测定,所得相同时间点各组OD值在统计学上没有差异(P>0.05),表皮干细胞生长速度各组间无差异.第1代表皮干细胞K19均有表达,而K14和K10表达均为阴性;其后高血清浓度(15%、20%)培养基中细胞较低血清浓度(0%、5%)先出现K14、K10蛋白的表达;培养至第10代是各组细胞均出现K10高表达,而K19、K14表达阴性.结论:在低血清浓度(0%、5%)的培养基中表皮干细胞生长良好,且能够相对较好保持表皮干细胞的特性.     

微载体浓度与细胞接种密度对ST细胞生长的影响

选择合适的微载体浓度、细胞接种密度以提高微载体利用率,优化微载体培养体系猪睾丸细胞(Swine testicle cells)的贴附生长与维持。使用DMEM补加10%血清、LSM(Low serum medium)两种培养基考察微载体浓度、细胞接种密度对细胞生长维持的影响,进而比较ST细胞在不同条件下对Cytodex1微载体的利用率。结果显示,使用LSM在T150方瓶中连续传代培养30d,平均比生长速率为0.626d~(0-1),是DMEM补加10%FBS培养基的1.15倍。选择10×10~5cells/mL细胞接种3g/LCytodex1搅拌瓶体系,最大细胞密度为38.3×10~5cells/mL,微载体利用率上升到58.8%。在灌注培养体系中培养ST细胞15d,最终细胞密度达到36.6×10~5cells/mL,扩增了13.6倍。微载体悬浮培养的使用一方面有利于ST细胞的贴附与生长,实现高密度生长,另一方面增加了微载体的使用成本,选择合适的微载体浓度、细胞接种密度,能够最大化利用微载体与培养基中的营养物质实现细胞的最优生长。     

用含10%胎牛血清的DMEM培养肠出血性大肠杆菌O157∶H7可增强其对HeLa细胞的黏附/擦拭损伤

目的:研究生长在不同培养基中的肠出血性大肠杆菌(EHEC)O157∶H7对宿主细胞造成的黏附/擦拭损伤是否存在差异。方法:分别用LB、DMEM、DMEM(含10%胎牛血清)、DMEM(含终浓度为25mmol/L的HEPES)等4种培养基培养O157∶H7,然后感染HeLa细胞,利用Giemsa染色观察细菌黏附差异,进行肌动蛋白荧光染色实验并观察宿主细胞肌动蛋白聚集差异。结果:在含10%胎牛血清的DMEM培养基中培养EHECO157∶H7,其黏附力增加,聚集细胞骨架肌动蛋白的能力明显增强。结论:为进一步研究EHECO157∶H7的致病性,探索O157∶H7新的致病因子奠定了基础。     

中华仓鼠卵巢(CHO)工程细胞无血清培养的研究

以DMEM：F12(1：1)为基础培养基,通过观察细胞生长状态和检测乙肝表面抗原的表达量作为评价指标,筛选适合于CHO工程细胞生长的生长因子,如：胰岛素、转铁蛋白、氢化可的松、硒酸钠,丁二胺等。并且建立了J5SFM培养基。该培养基与商品化的无血清培养基比较,能够使细胞生长维持较长的时间,表达产物分泌量也相对较高。     

趋磁细菌W M-1 的培养条件优化研究

采用正交设计实验法研究了趋磁细菌WM-1产磁性细胞的培养条件。并利用L16(44)方案,用16个实验完成了4种培养条件、4个水平的优化工作。研究结果表明,培养基的pH值是影响趋磁细菌WM-1产磁性细胞的重要因素,正交实验结果在90％的置信区间可信。在最优的培养条件下,即pH为7．0,氧气的浓度为4％,m酒石酸:m琥珀酸为1:1,NaNO3 100 mg l-1条件下,磁性细胞的浓度提高到6．5×107 cells ml-1,比优化前提高了约8．3％．趋磁细菌WM-1磁滞回线的测量表明,Hc=230 Oe,Ms=0．9 emu／g dry wt．Cells,及Mr／Ms=0．50。     

Effectiveness of autologous serum as an alternative to fetal bovine serum in adipose-derived stem cell engineering

In cell culture, medium supplemented with fetal bovine serum is commonly used, and it is widely known that fetal bovine serum supplies an adequate environment for culture and differentiation of stem cells. Nevertheless, the use of xenogeneic serum can cause several problems. We compared the effects of four different concentrations of autologous serum (1, 2, 5, and 10 %) on expansion and adipogenic differentiation of adipose-derived stem cells using 10 % fetal bovine serum as a control. The stem cells were grafted on nude mice and the in vivo differentiation capacity was evaluated. The isolation of adipose-derived stem cells was successful irrespective of the culture medium. The proliferation potential was statistically significant at passage 2, as follows: 10 % autologous serum >10 % fetal bovine serum = 5 % autologous serum >2 % autologous serum = 1 % autologous serum. The differentiation capacity appeared statistically significant at passage 4, as follows: 10 % fetal bovine serum >10 % autologous serum = 5 % autologous serum >2 % autologous serum = 1 % autologous serum. Ten percent autologous serum and 10 % fetal bovine serum had greater differentiation capacity than 1 and 2 % autologous serum in vivo, and no significant difference was observed between the groups at ≥5 % concentration at 14 weeks. In conclusion, 10 % autologous serum was at least as effective as 10 % fetal bovine serum with respect to the number of adipose-derived stem cells at the end of both isolation and expansion, whereas 1 and 2 % autologous serum was inferior.     

Physiological quiescence in plasma-derived serum: Influence of platelet-derived growth factor on cell growth in culture

A platelet-derived growth factor can be shown to be the principal stimulant of DNA synthesis in whole blood serum for those cells that require serum for maintenance and growth in culture. Cell free plasma-derived serum lacks such platelet-derived material. 3T3 cells and primate arterial smooth muscle cells can be maintained in a quiescent state in culture for as long as six weeks in plasma-derived serum. Such cells can grow logarithmically after exposure to 5% whole blood serum or as little as 100 ng/ml of partially purified platelet factor. The cell cycle of smooth muscle cells has been studied in the quiescent (5% plasma-derived serum) and growing state (5% whole blood serum or 5% plasma-derived serum plus platelet factor). The generation time of smooth muscle cells is 16 to 18 hours as shown by autoradiographic frequency of labelled mitoses. The generation time is the same for cells in the growth fraction in either 5% whole blood serum or 5% plasma-derived serum. Thus, platelet factor acts by recruiting cells into the growth fraction rather than effecting a change in the duration of the cell cycle. Flow microfluorimetry studies on cells growing logarithmically in 5% whole blood serum give the following phase durations: G₁ = 5.6 hours; S = 7.6 hours; and G₂ + M = 3.8 hours. Based on these studies the argument is presented that cells cultured in 5% plasma-derived serum provide a more physiological base for the study of quiescence than do cells in low concentrations of whole blood serum or confluent, density inhibited cells at high (5% or greater) concentrations of whole blood serum. Furthermore, 5% plasma-derived serum represents an appropriate state to examine the perturbation of quiescent cells.     

Serum‐free scaled up expansion and differentiation of murine embryonic stem cells to osteoblasts in suspension bioreactors

The use of embryonic stem cell (ESC) derived cells has emerged as a potential alternative treatment for a number of degenerative diseases, including musculoskeletal diseases. Conventional ESC culturing methods use fetal bovine serum (FBS) as a major supplemental component of culture media, which is undesirable for clinical applications. These cultures are usually performed in small‐scale static vessels (gelatin‐coated dishes), which limit the number of cells that can be generated. It is essential to develop effective, reproducible protocols for efficient scalable production of ESC‐derived cells. Here we present serum‐free bioreactor protocols for (1) expansion and (2) differentiation of embryonic stem cells to osteoblasts. Cultivation of mESCs in serum‐free media, supplemented with 15% knockout serum replacement (KSR) resulted in a 27.1‐ and 48.6‐fold expansion in static culture and suspension respectively by day 5 of culture. Further induction to osteoblasts with a differentiation cocktail was verified by up‐regulation of osterix and osteocalcin. Mineralization was also enhanced, as indicated by an increase in the calcium deposition by osteogenic cells by day 28. These results will serve as the basis for developing protocols with human ESCs as a new treatment alternative for musculoskeletal diseases. Biotechnol. Bioeng. 2010;106: 829–840. © 2010 Wiley Periodicals, Inc.     

Promotion of Neuritogenesis in Mouse Neuroblastoma Cells by Exogenous Gangliosides. Relationship Between the Effect and the Cell Association of Ganglioside GM1

Ganglioside GM1 promoted neuritogenesis of neuroblastoma cells, neuro-2a clone, in monolayer culture. GM1 bound to neuro-2a cells in three distinct forms, one removable by treatment with serum-containing solutions, one serum-resistant and labile to trypsin treatment, and one resistant to serum and trypsin treatments. The proportions among the three forms of cell-associated GM1 varied in relation to duration of exposure to ganglioside, ganglioside concentration in the medium, and number of cells in culture. The form removable by serum was predominant at the initial stages of association and at the highest ganglioside concentrations (over 10(-6)M); the trypsin-labile and -stable forms tended to increase with increasing cell number and decreasing ganglioside concentration. The neuritogenic effect of GM1 was higher when neuro-2a cells were incubated for 24 h in the presence of GM1 and fetal calf serum. Under this condition the percentage of neurite-bearing cells increased from 11% of control to 62% at the optimal ganglioside concentration of 10-4M. The effect was still present, although to a lower extent (from 11% to 28% of neurite-bearing cells), when cells were first exposed for only 2 h to GM1, then washed and incubated for 24 h in the presence of fetal calf serum. The trypsin-labile and -stable forms of cell-associated GM1 had a fundamental role in the effect, whereas the form removable by serum was not involved. The preparation of GM1 used was extremely pure (99%) and, in particular, had a peptide contamination, if any, less than 1:20,000-1:50,000.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of calcium in serum-stimulation of hexose transport in muscle cells

Serum stimulates glucose uptake into several cells in culture. In intact muscle, an increase in cytosolic free Ca2+ has been proposed to mediate the activation of glucose uptake by hormones and other stimuli [Cell Calcium (1980) 1, 311-325]. We report that hexose (2-deoxy-D-glucose) uptake into L6 muscle cells in culture is enhanced several-fold by fetal calf serum. The increase in uptake is due to stimulation of transmembrane transport, since serum also stimulated uptake of the non-metabolizable hexose 3-O-methyl-D-glucose. The role of Ca2+ in this stimulation was assessed: (i) stimulation of transport by serum was independent of the presence of extracellular Ca2+ during the incubation with serum; (ii) the intracellular levels of free Ca2+, measured by the fluorescence of the novel Ca-indicator quin-2, were identical in serum-stimulated and control cells. It is concluded that hexose transport can increase in muscle cells without concomitant changes in cytoplasmic free Ca2+.     

Production of monoclonal antibody using free-suspended and immobilized hybridoma cells: Effect of serum

The effect of serum on cell growth and monoclonal antibody (MAb) productivity was studied in a repeated fedbatch mode using both free-suspended and immobilized S3H5/gamma2bA2 hybridoma cells. In the suspension culture, serum influenced the cell growth rate but not the specific MAb productivity. The average specific growth rate of the suspension culture in medium containing 10% serum was approximately 0.99 +/- 0.12 day(-1) (+/-standard deviation), while that in medium containing 1% serum was approximately 0.73 +/- 0.12 day(-1). The specific MAb productivity was almost constant at 3.69 +/- 0.57 mug/10(6) cells/day irrespective of serum concentration reached a maximum at ca. 1.8 x 10(6) cells/mL of medium in 10% serum medium, and the cell concentration was gradually reduced to 1%. The specific MAb productivity of the immobilized cells was more than three times higher than that of the free-suspended cells. The amount of serum in the medium did not influence the specific MAb production rate of the immobilized cells. The maintenance of high cell concentration and the enhanced specific MAb productivity of the immobilized cell culture resulted in a higher volumetric MAb productivity. In addition, MAb yield in the immobilized cell culture with medium containing 1% serum was 2.2 mg/mL of serum, which was approximately three times higher than that in the suspension culture.     

Timing of sequential changes in cumulus cells and first polar body extrusion during in vitro maturation of buffalo oocytes

Studies were conducted to investigate the degree of the cumulus cell expansion and expulsion of the first polar body in relation to time of incubation in three different culture media during in vitro maturation of buffalo oocytes and to suggest a suitable practical method for assessment of in vitro maturation rate of buffalo oocytes. Buffalo oocytes were aspirated from ovaries collected from a local slaughterhouse. Only oocytes with more than two layers of cumulus cells and homogenous ooplasm were cultured into 50 microl droplets of three different culture systems: (1) TCM-199 + steer serum (10%): (2) TCM-199 + steer serum (10%) + PMSG (40 IU/ml); and (3) TCM-199 + steer serum (10%) + PMSG (40 IU/ml) + estradiol 17beta (1 microg/ml) in a 35 mm Petri dish. The droplets were covered with warm (39 degrees C) mineral oil and incubated in a CO2 incubator (39 degrees C, 5% CO2 in air, 90-95% relative humidity) for 16-18, 20, 22, and 24 h. The maturation rate was assessed by evaluation of degree of cumulus cells expansion and identifying first polar body extrusion into the perivitelline space under stereo zoom microscope. Matured oocytes were inseminated in vitro with 9-10 million sperm/ml of Brackett and Oliphant (BO) medium. Cleaved embryos were cultured in TCM-199 supplemented with steer serum (10%) for 8 days. Cumulus expansion and extrusion of first polar body commenced at 16 and 17 h, respectively, of buffalo oocyte culture. These events mainly exhibited during 22-24 h of culture. Oocytes with Degrees 1 and 2 cumulus cells expansion and extruded first polar body in degree 0 oocytes may be considered as matured and can be used in IVF studies.     

Modulation of the G0 to S phase transit time by insulin: Potential involvement of protein phosphorylation

BHK fibroblasts can be growth arrested by incubation in low serum (0.1%) medium. Growth is initiated by incubating cells in high serum (10%) medium. We have found that if the quiscent cells in low serum medium are incubated with insulin, the G₀ to S transit time is decreased by two to six hours when serum (10%) is added back to the culture. The effect of insulin treatment of quiescent cells on the cellular phosphoprotein profile was examined. It was found that insulin stimulated the phosphorylation of a 96,000 dalton cytosol protein. This protein is also intensely phosphorylated in proliferating cells and may be one of the critical intracellular events to occur when a cell initiates growth.     

The highly unnatural fatty acid profile of cells in culture

The fatty acid profile of cells in culture are unlike those of natural cells with twice the monounsaturated (MUFA) and half the polyunsaturated fatty acids (PUFA) level (Mol%). This is not due to cell lines primarily being derived from cancers but is due to limited access to lipid and an inability to make PUFA de novo as vertebrate cells. Classic culture methods use media with 10% serum (the only exogenous source of lipid). Fetal bovine serum (FBS), the serum of choice has a low level of lipid and cholesterol compared to other sera and at 10% of media provides 2–3% of the fatty acid and cholesterol, 1% of the PUFA and 0.3% of the essential fatty acid linoleic acid (18:2n-6) available to cells in the body. Since vertebrate cell lines cannot make PUFA they synthesise MUFA, offsetting their PUFA deficit and reducing their fatty acid diversity. Stem and primary cells in culture appear to be similarly affected, with a rapid loss of their natural fatty acid compositions. The unnatural lipid composition of cells in culture has substantial implications for examining natural stems cell in culture, and for investigations of cellular mechanisms using cell lines based on the pervasive influence of fats.